Field
The present disclosure relates to techniques for communicating optical signals. More specifically, the present disclosure relates to wavelength-locking a ring-resonator modulator.
Related Art
Silicon photonics is a promising technology that can provide large communication bandwidth, low latency and low power consumption for inter-chip and intra-chip connections. In the last few years, significant progress has been made in developing low-cost components for use in inter-chip and intra-chip silicon-photonic connections, including: high-bandwidth efficient silicon modulators, low-loss optical waveguides, wavelength-division-multiplexing (WDM) components, and high-speed CMOS optical-waveguide photo-detectors. However, the performance of many of these components is dependent on temperature and/or wavelength changes, which remains an obstacle to implementing silicon-photonic links.
For example, silicon modulators, such as ring-resonator modulators, are used in silicon-photonic links (and in photonic communication in general) to convert electrical signals into modulated optical signals. However, ring-resonator modulators typically work over a very small predefined range of wavelengths. Consequently, variations in the carrier wavelengths of optical signals output from optical sources (such as lasers), as well as changes in the index of refraction of optical waveguides because of fabrication tolerances, temperature fluctuations and/or self-heating of the ring-resonator modulators, can degrade the performance of ring-resonator modulators. In particular, a 1 C temperature change may cause a 110 pm shift in the resonance wavelength of the ring-resonator modulator, which can completely overpower voltage modulation of the ring-resonator modulator.
Hence, what is needed is a ring-resonator modulator without the above-described problems.